1. Field of the Invention
This invention relates to the removal of odorous sulfur compounds from potable water. Briefly, water from a well and compressed air are sprayed from a fog nozzle into a treating tank to maintain a predetermined water level in the tank, while, whenever the pressure at the top of a pressurized de-aerating tank falls below a predetermined level, water is pumped from the bottom of the treating tank into a pressurized filter vessel which is open to the de-aerating tank. Compressed air is introduced into the filter vessel whenever water is pumped thereinto. Air, water and sulfur compounds are vented from a level in the treating tank higher than the predetermined water level; air is also discharged from the top of the de-aerating tank, flowing through a self sensing air valve. Water flows from the de-aerating tank in response to demands from a distribution system. It is advantageous for the upper part of the treating tank to be packed with spheres over which the fogged water and air in that portion of the tank flow before collecting in the lower portion of the tank. Water which is pumped to the filter vessel enters through a control module, flows downwardly through a filter medium and into and upwardly through a central tube and the discharge side of the control module, and to the de-aerating tank.
2. The Prior Art
The instant invention is deemed to constitute an improvement over U.S. Pat. No. 4,992,181WATER TREATMENT METHOD, Feb. 12, 1991, which discloses the desulfurization of water in apparatus comprising a vessel 10 in which the water is sprayed upwardly through air, a standpipe 11 in which water is sprayed through air from a nozzle 26 "to maintain a given pressure, say 40 psig (about 1/4 MPa), in the standpipe 11", a vessel 13 which contains a fluidized bed of activated carbon and a green sand or zeolite filter 17. Some sulfur is removed by aeration in the vessel 11, while the rest is removed by the bed of activated carbon. The patent also discloses (see the paragraph which commences in line 32 of column 4) that column packing material can be used to promote or accelerate the aeration of feed water in a vessel 41 (FIG. 2), naming "Jaeger Tri-Packs.RTM. column packing balls" as suitable. The patent includes the following sentence (column 4, lines 61 and following):
"It is further contemplated that the use of column packing material, including a catalyst, in the vessel 41, the standpipe 11, or both, may obviate the use of the vessel 13 and contents, the vessel 16 and contents, or both."
The patent does not indicate that it was ever demonstrated that "the use of column packing material, including a catalyst," did obviate the use of either or both of the vessels 13 and 16 and their contents.
The following patents (all U.S.) have also been considered, but are not deemed to disclose or suggest the instant improvements:
U.S. Pat. No.323,432, Aug. 4, 1885: this patent relates to the purification of water by forcing air into a stream of water that is flowing in a pipe.
U.S. Pat. No. 835,886, Nov. 13, 1906: while the patent relates to the aeration of water, it is distilled water that is aerated; the use of a fogging nozzle is not suggested; and the aeration pressure is not disclosed.
U.S. Pat. No. 938,075, Oct. 26, 1909: this patent discloses apparatus for "high pressure" treatment of water to remove iron and similar impurities. The water is discharged from a pipe 9 into an open pan 10, overflowing into pans 11 and 12, and falling through "high pressure" air. It does not appear that an actual pressure is named.
U.S. Pat. No. 1,985,435, Dec. 25, 1934: a mixture of air and water from a pump 7 is discharged into an aerator which operates at ambient pressure. The water flows by gravity from a first to a second to a third spray pan 21, and is then filtered and pumped to a storage tank.
U.S. Pat. No. 2,200,580, May 14, 1940: sewage and industrial wastes are caused to flow downwardly through a bacterially active contact mass in the presence of "an oxygen-containing gas such a air".
U.S. Pat. No. 2,591,134, Apr. 1, 1952: water is sprayed upwardly through air at atmospheric pressure against a baffle and then falls into water in a tank 4.
U.S. Pat. No. 3,387,431, Jun. 11, 1968, discloses the desulfurization of water in a vessel 2. Small droplets of the water are sprayed from a nozzle 3 into the interior of a tube 4 which extends through a bed 5 of iron oxide or of another material that reacts with hydrogen sulfide. The water droplets entrain air from above the bed 5, which flows downwardly with the water through the tube 4. The pressure of the water sprayed is 10 psi. higher than that of the air in the vessel 2. Desulfurized water is collected in a reservoir 6, from which is flows through an outlet pipe 7 for use. A gaseous mixture of air and H.sub.2 S removed from the water flows upwardly through the bed of iron oxide or other material which reacts with the H.sub.2 S to remove the sulfur, so that only the air reaches the top of the bed.
U.S. Pat. No. 3,543,937, Dec. 1, 1970: discloses the use of thin walled spheres made of a synthetic resin as packing in a filter on which sewage and organic industrial wastes are sprayed.
U.S. Pat. No. 4,097,201, Jun. 27, 1978, discloses the desulfurization of underground water inside a well casing 12. Compressed air is discharged from "an air screen and outlet assembly 36", "to purge the well water of corrosive gases such as sulphur gas". Air and "sulphur gas" (H.sub.2 S) are vented from a vertical standpipe 42, while a downwell pump 50 discharges desulfurized water into a service line 58.
U.S. Pat. No. 4,544,488, Oct. 1, 1985: this patent discloses the removal of benzene, xylene, toluene, and halogenated aliphatic hydrocarbons from groundwater using an induced draft stripper which has a "spray tree" at one end and "eliminators" at the other, followed by carbon treatment; the patent does not disclose a fogging nozzle. Pressures up to about 45 psig are reported, but these appear to be the pressures of water serving the spray tree, which is necessarily higher than the pressure inside the stripper.
U.S. Pat. No. 4,582,610, Apr. 15, 1986: this patent discloses water aeration apparatus where a part of the water pumped from a well is sprayed inside a casing where it falls through air in the casing back into the well. Apparently, the air would be at atmospheric pressure. The patent says it is preferable for 30 to 50 percent of the water pumped to be returned to the well.
U.S. Pat. No. 4,892,664, Jan. 9, 1990: water contaminated with volatile organic chemicals is delivered by a spray head onto the top of packing (e.g., Jaeger Tri-Packs, polypropylene spheroids 2 inches in diameter) and flows downwardly through the packing, countercurrent to air. The air is blown into the bottom of the packed column, is treated to destroy the volatile organic chemicals released to it from the contaminated water, and is discharged through a vent to the atmosphere. Presumably, the air in the packed column is at essentially atmospheric pressure.
U.S. Pat. No. 5,045,215, Sep. 3, 1991: water contaminated with radon and volatile organic chemicals, xylene, toluene and halogenated hydrocarbons being named, is sprayed as a "fine mist" in an aerator that is pressurized to about 3 to 4 inches of water.
U.S. Pat. No. 5,069,796, Dec. 3, 1991: this patent discloses the removal of benzene, xylene and toluene from groundwater using a packed spray tower through which the ground water flows downwardly, countercurrent to air, and a carbon bed. The packed spray tower apparently operates at ambient pressure; a fogging nozzle is not disclosed.